Recent studies suggest that exposure to electromagnetic radiation (EMR) is associated with an excess risk of adverse reproductive events. While the evidence from these studies is not conclusive it is significant enough to raise concerns about occupations with an associated exposure to EMR. Physical therapists (PT) represent one such occupation with exposure to a range of EMR frequencies. A majority of PTs are females of reproductive age, half of whom have expreienced some occupational exposure to EMR. This is the second submission of this proposal. We have modified the study plan and we propose to conduct a preliminary study to determine if female PTs with exposure to EMR are at higher risk of reproductive hazards than female PTs without such exposure. With the cooperation of the American Physical Therapy Association (APTA), we propose to conduct a preliminary non- concurrent prospective study. A mailed questionnaire survey form, which has been extensively pretested, will be sent to 35,000 current and former PTs. The questionnaire is designed for mass mailing, and based on responses during the pretest will be designed to facilitate recall of occupational exposures associated with work as a PT, including a detailed precoded history of exposure to potential sources of EMR. In addition, the questionnaire is designed to obtain data on reprouctive history and exposure to known risk factors. Based on the APTA's experience in automated mailings to its members and our experience during the pretest, we expect a 45 percent response to the first mailing and a total response rate of 71 percent after three mailings. In this preliminary study we will determine if there is evidence of an excess risk of reproductive hazards in female PTs. More extensive studies are not warranted at this time. However if evidence of excess risk is found in this preliminary study additional studies will be planned to confirm the excess risk and to more precisely determine if the risk is, in part or whole, attributable to EMR exposure. Other studies under consideration include a nested case-control study of femal PTs as a follow-up to the preliminary survey and onsite exposure assessment surveys of PTs exposed to EMR.